Opportunity at National Institute of Standards and Technology (NIST)
Multiscale Modeling of Interfacial Environments around Carbon Nanotubes
Material Measurement Laboratory, Materials Science and Engineering Division
Please note: This Agency only participates in the February and August reviews.
|Jeffrey Alan Fagan
|Frederick R. Phelan
|Daniel William Siderius
Interactions of nanoparticles with their local environment are strongly modulated by any interfacial layer coating the nanoparticle. In particular for carbon nanotubes, which are comprised entirely of surface atoms, the interfacial layer often dominantly controls the interactions of and between nanotubes dispersed for processing in liquid media. A key example of this is that liquid phase separation techniques rely on modulating these interactions using mixtures of interfacially adsorbing surfactants to extract nanotubes of different species, chiral angle, metalicity, or enatiomeric structure. Although specific mixtures of adsorbing molecules and experimental conditions have been identified that allow for heuristic design of separations, the connections between the chemistry and structure of adsorbing molecules and the resulting interfacial layer and its attributes are poorly understood. In this opportunity, we seek to perform simulations of nanotubes in solution with the ultimate goal of more fundamentally understanding the physicochemical and thermophysical properties of the interfacial layer on nanotubes in solution. This will involve evaluation of the interactions between a nanotube and the project examples include simulations of systems that incorporate ion distributions both inside and outside the nanotube surface, examination of the specific effects of chemical structure on the adsorption of molecules to the nanotube surface and its effect on solubility, and course-grained simulations of nanotubes with large adsorbed dispersant molecules in solution. It is expected that the challenging nature of these simulations will require the development of novel simulation techniques. In addition, simulations and examination of the overall separation process may require computational studies across multiple length scales.
Modeling; Nanotube; Molecular simulation; Interface; Coarse-grain; Thermodynamics; Computational chemistry; Nanotechnology; Statistical mechanics;
Open to U.S. citizens
Open to Postdoctoral applicants